Naive implementation. Just make the padding bigger
Check these screenshots notice that the left text doesn't line up perfectly. I don't think that's an issue, but I defer to design for that one.
However, coding up a dynamic solution may be non-trivial. Not hard, but we'd have to find if any number in any of the data arrays is greater than 999 then adjust padding upward if so. Not a big deal on small data arrays, but we don't have absolute control over how big these might be
Original
Padding < 1000
Padding > 1000
Padding > 1,000,000
Note regarding the above. D3 intelligently caps this at 3 digits + 1 character. So that is the maximum width Y will ever be.
